Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have an Acer laptop I've been toying with, at some point I backed up the 'Acer recovery' hidden partition using dd.
iirc I used a LiveCD and something like:

dd if=/dev/sda1 of=/mnt/remote/acer.img

to store the 'partition'. I did not backup the entire drive. The resulting file is:

5239471104 acer.aspire.5600.recovery.partition.img

After that, I wiped the partition table and installed Ubuntu Netbook remix.

Knowing that the .img size is:5239471104 bytes and the recovery partition was a hidden, primary near the start of the disk. What would I need to do, if I wanted to wipe the partition table again and re-create this 'recovery' partition exactly as it was?

As an extra question, if anyone happens to know:
Granted that I did not backup the entire disk, and the MBR has since been overwritten, would I be missing the 'recovery' functionality Acer laptops have? I am referring to using alt-F10 during BOOT to switch to Acer's recovery/installation environment.
( I'm guessing this is a BIOS function and not a boot-loader function, so if the partition is re-created exactly the way the BIOS recovery loader expects it to be, it should work, but that's just a guess )

share|improve this question
up vote 1 down vote accepted

It's just an "MS Data" (MBR partitioning type 0x0C) volume. So create a primary MS Data volume and restore the image to it.

Unfortunately, Acer's recovery utility also requires Acer-specific code in the Master Boot Record for the recovery procedure to work exactly as one expects. The Acer MBR boostrap code image is, fortunately however, stored in an rtmbr.bin file in the recovery partition itself, in a tools subdirectory. You should be able to extract the image file from the volume image using something like mtools.

Restoring the MBR image from that file once extracted is tricky under Linux, because one has to remember to not copy the entire 512 bytes of the image, as the dd command will do by default, because that will overwrite the MBR partition table's four primary partition entries and effectively erase your whole partition table. Restoring the MBR image is a lot easier under Windows by dint of the simple fact that Acer supplies a Windows utility program that can do it. It's mbrwrwin.exe in the very same directory as the rtmbr.bin file, and the command to restore the Acer MBR image is

mbrwrwin.exe install rtmbr.bin
(Older versions are mbrwrdos.exe and rtmbrnb.bin.)

On the gripping hand, one doesn't, strictly speaking, need the Acer MBR. It's there to force the Acer "PQSERVICE" volume to be bootstrapped instead of whatever partition is actually the active partition. One can equally well just bootstrap the Acer partition directly — from within a boot manager, say — and not worry about the Acer MBR bootstrap.

The bad news is that the Acer restore utility is fussy about what it will restore over, in particular about how many and what types of partitions are in the partition table. But that's properly the subject of another question and answer.

share|improve this answer
Very good info. Do you happen to know a method to create a partition exactly the size it would need to be? (I'm guessing it might need 5239471104 bytes, not 100% sure tho) – DM8 Jun 29 '11 at 20:19
If it hasn't been asked already, it's worth asking that as a primary question in its own right: "How do I create a partition of a particular specified size?" The answer is going to vary by partition table utility. – JdeBP Jun 30 '11 at 9:24

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.